MCQ on Case of Medical Industries

A 42 year old man who has industrial exposure to benzene, complains of fatigue, abdominal fullness and night sweats. Finally, because his wife insists, he sees his doctor. On physical examination, he is found to have a low grade fever and dramatic splenomegaly. His doctor comments that he has never seen such splenomegaly. Laboratory tests are done, including a CBC with differential. His white blood count is 150,000/cu mm. His blood smear shows mature granulocytes, a few immature granulocytes and basophilia. No Auer rods are visualized. He is positive for Philadelphia chromosome. Which of the following is most likely?

a) acute lymphoblastic leukemia
b) acute myelogenous leukemia
c) chronic lymphoblastic leukemia
d) chronic myelogenous leukemia
e) hairy cell leukemia

The correct answer is D

Explanation
This patient is the average age for the onset of CML. Exposure to benzene is a known risk factor. Fatigue, night sweats, low grade fever and abdominal fullness secondary to splenomegaly are all symptoms that can be associated with CML The splenomegaly in CML can be marked. The laboratory findings in chronic myelogenous leukemia will show an elevated granulocytic counts, as in this scenario. Basophilia can also be seen with CML. The Philadelphia chromosome, a translocation between chromosome 22 and 9, is positive in the vast majority (90-95%) of patients with chronic myelogenous leukemia.In acute lymphoblastic leukemia (choice a) there would be numerous blast cells in the peripheral smear. ALL tends to occur in children with an average age of 4 (however, it can occur in adults).In acute myelogenous leukemia (choice b) there would be numerous blast cells in the peripheral smear. AML tends to strike adults. The presence of Auer rods indicates AML.In chronic lymphocytic leukemia (choice c) there would be a lymphocytosis with mature looking cells. CLL occurs in older people.Hairy cell leukemia (choice e) has distinctive cells present in the peripheral blood smear, called 'hairy cells'